Initial commit of the diameter application.

The application provides an implementation of the Diameter protocol
as defined in RFC 3588.

1 files changed, 788 insertions, 0 deletions

diff --git a/lib/diameter/src/compiler/diameter_codegen.erl b/lib/diameter/src/compiler/diameter_codegen.erl
new file mode 100644
index 0000000000..213ba0d22c
--- /dev/null
+++ b/lib/diameter/src/compiler/diameter_codegen.erl
@@ -0,0 +1,788 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2010-2011. 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
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(diameter_codegen).
+
+%%
+%% This module generates .erl and .hrl files for encode/decode
+%% modules from the orddict parsed from a .dia (aka spec) file by
+%% dis_spec_util. The generated code is very simple (one-liners), the
+%% generated functions being called by code included from dis_gen.hrl
+%% in order to encode/decode messages and AVPs. The orddict itself is
+%% returned by dict/0 in the generated module and dis_spec_util calls
+%% this function when importing spec files. (That is, beam has to be
+%% compiled from an imported spec file before it can be imported.)
+%%
+
+-export([from_spec/4]).
+
+%% Internal exports (for test).
+-export([file/1,
+         file/2,
+         file/3]).
+
+-include_lib("diameter/src/app/diameter_internal.hrl").
+-include("diameter_forms.hrl").
+
+%% Generated functions that could have no generated clauses will have
+%% a trailing ?UNEXPECTED clause that should never execute.
+-define(UNEXPECTED(N), {?clause, [?VAR('_') || _ <- lists:seq(1,N)],
+                        [],
+                        [?APPLY(erlang,
+                                error,
+                                [?TERM({unexpected, getr(module)})])]}).
+
+
+from_spec(File, Spec, Opts, Mode) ->
+    Outdir = proplists:get_value(outdir, Opts, "."),
+    putr(verbose, lists:member(verbose, Opts)),
+    putr(debug,   lists:member(debug, Opts)),
+    codegen(File, Spec, Outdir, Mode).
+
+%% Optional reports when running verbosely.
+report(What, Data) ->
+    report(getr(verbose), What, Data),
+    Data.
+
+report(true, Tag, Data) ->
+    io:format(">>~n>> ~p ~p~n", [Tag, Data]);
+report(false, _, _) ->
+    ok.
+
+putr(Key, Value) ->
+    put({?MODULE, Key}, Value).
+
+getr(Key) ->
+    get({?MODULE, Key}).
+
+%% ===========================================================================
+%% ===========================================================================
+
+%% Generate from parsed spec in a file.
+
+file(F) ->
+    file(F, spec).
+
+file(F, Mode) ->
+    file(F, ".", Mode).
+
+file(F, Outdir, Mode) ->
+    {ok, [Spec]} = file:consult(F),
+    from_spec(F, Spec, Outdir, Mode).
+
+%% ===========================================================================
+%% ===========================================================================
+
+choose(true, X, _)  -> X;
+choose(false, _, X) -> X.
+
+get_value(Key, Plist) ->
+    proplists:get_value(Key, Plist, []).
+
+write(Path, [C|_] = Spec)
+  when is_integer(C) ->
+    w(Path, Spec, "~s");
+write(Path, Spec) ->
+    w(Path, Spec, "~p.").
+
+w(Path, Spec, Fmt) ->
+    {ok, Fd} = file:open(Path, [write]),
+    io:fwrite(Fd, Fmt ++ "~n", [Spec]),
+    file:close(Fd).
+
+codegen(File, Spec, Outdir, Mode) ->
+    Mod = mod(File, orddict:find(name, Spec)),
+    Path = filename:join(Outdir, Mod),  %% minus extension
+    gen(Mode, Spec, Mod, Path),
+    ok.
+
+mod(File, error) ->
+    filename:rootname(filename:basename(File));
+mod(_, {ok, Mod}) ->
+    atom_to_list(Mod).
+
+gen(spec, Spec, _Mod, Path) ->
+    write(Path ++ ".spec", Spec);
+
+gen(hrl, Spec, Mod, Path) ->
+    gen_hrl(Path ++ ".hrl", Mod, Spec);
+
+gen(erl = Mode, Spec, Mod, Path)
+  when is_list(Mod) ->
+    gen(Mode, Spec, list_to_atom(Mod), Path);
+
+gen(erl, Spec, Mod, Path) ->
+    putr(module, Mod),  %% used by ?UNEXPECTED.
+
+    Forms = [{?attribute, module, Mod},
+             {?attribute, compile, [{parse_transform, diameter_exprecs}]},
+             {?attribute, compile, [nowarn_unused_function]},
+             {?attribute, export, [{name, 0},
+                                   {id, 0},
+                                   {vendor_id, 0},
+                                   {vendor_name, 0},
+                                   {decode_avps, 2}, %% in diameter_gen.hrl
+                                   {encode_avps, 2}, %%
+                                   {msg_name, 2},
+                                   {msg_header, 1},
+                                   {rec2msg, 1},
+                                   {msg2rec, 1},
+                                   {name2rec, 1},
+                                   {avp_name, 2},
+                                   {avp_arity, 2},
+                                   {avp_header, 1},
+                                   {avp, 3},
+                                   {grouped_avp, 3},
+                                   {enumerated_avp, 3},
+                                   {empty_value, 1},
+                                   {dict, 0}]},
+             %% diameter.hrl is included for #diameter_avp
+             {?attribute, include_lib, "diameter/include/diameter.hrl"},
+             {?attribute, include_lib, "diameter/include/diameter_gen.hrl"},
+             f_name(Mod),
+             f_id(Spec),
+             f_vendor_id(Spec),
+             f_vendor_name(Spec),
+             f_msg_name(Spec),
+             f_msg_header(Spec),
+             f_rec2msg(Spec),
+             f_msg2rec(Spec),
+             f_name2rec(Spec),
+             f_avp_name(Spec),
+             f_avp_arity(Spec),
+             f_avp_header(Spec),
+             f_avp(Spec),
+             f_enumerated_avp(Spec),
+             f_empty_value(Spec),
+             f_dict(Spec),
+             {eof, ?LINE}],
+
+    gen_erl(Path, insert_hrl_forms(Spec, Forms)).
+
+gen_erl(Path, Forms) ->
+    getr(debug) andalso write(Path ++ ".forms", Forms),
+    write(Path ++ ".erl",
+          header() ++ erl_prettypr:format(erl_syntax:form_list(Forms))).
+
+insert_hrl_forms(Spec, Forms) ->
+    {H,T} = lists:splitwith(fun is_header/1, Forms),
+    H ++ make_hrl_forms(Spec) ++ T.
+
+is_header({attribute, _, export, _}) ->
+    false;
+is_header(_) ->
+    true.
+
+make_hrl_forms(Spec) ->
+    {_Prefix, MsgRecs, GrpRecs, ImportedGrpRecs}
+        = make_record_forms(Spec),
+
+    RecordForms = MsgRecs ++ GrpRecs ++ lists:flatmap(fun({_,Fs}) -> Fs end,
+                                                      ImportedGrpRecs),
+
+    RecNames = lists:map(fun({attribute,_,record,{N,_}}) -> N end,
+                         RecordForms),
+
+    %% export_records is used by the diameter_exprecs parse transform.
+    [{?attribute, export_records, RecNames} | RecordForms].
+
+make_record_forms(Spec) ->
+    Prefix = prefix(Spec),
+
+    MsgRecs = a_record(Prefix, fun msg_proj/1, get_value(messages, Spec)),
+    GrpRecs = a_record(Prefix, fun grp_proj/1, get_value(grouped, Spec)),
+
+    ImportedGrpRecs = [{M, a_record(Prefix, fun grp_proj/1, Gs)}
+                       || {M,Gs} <- get_value(import_groups, Spec)],
+
+    {Prefix, MsgRecs, GrpRecs, ImportedGrpRecs}.
+
+msg_proj({Name, _, _, _, Avps}) ->
+    {Name, Avps}.
+
+grp_proj({Name, _, _, Avps}) ->
+    {Name, Avps}.
+
+%% a_record/3
+
+a_record(Prefix, ProjF, L) ->
+    lists:map(fun(T) -> a_record(ProjF(T), Prefix) end, L).
+
+a_record({Nm, Avps}, Prefix) ->
+    Name = list_to_atom(Prefix ++ atom_to_list(Nm)),
+    Fields = lists:map(fun field/1, Avps),
+    {?attribute, record, {Name, Fields}}.
+
+field(Avp) ->
+    {Name, Arity} = avp_info(Avp),
+    if 1 == Arity ->
+            {?record_field, ?ATOM(Name)};
+       true ->
+            {?record_field, ?ATOM(Name), ?NIL}
+    end.
+
+%%% ------------------------------------------------------------------------
+%%% # name/0
+%%% ------------------------------------------------------------------------
+
+f_name(Name) ->
+    {?function, name, 0,
+     [{?clause, [], [], [?ATOM(Name)]}]}.
+
+%%% ------------------------------------------------------------------------
+%%% # id/0
+%%% ------------------------------------------------------------------------
+
+f_id(Spec) ->
+    Id = orddict:fetch(id, Spec),
+    {?function, id, 0,
+     [{?clause, [], [], [?INTEGER(Id)]}]}.
+
+%%% ------------------------------------------------------------------------
+%%% # vendor_id/0
+%%% ------------------------------------------------------------------------
+
+f_vendor_id(Spec) ->
+    {Id, _} = orddict:fetch(vendor, Spec),
+    {?function, vendor_id, 0,
+     [{?clause, [], [], [?INTEGER(Id)]}]}.
+
+%%% ------------------------------------------------------------------------
+%%% # vendor_name/0
+%%% ------------------------------------------------------------------------
+
+f_vendor_name(Spec) ->
+    {_, Name} = orddict:fetch(vendor, Spec),
+    {?function, vendor_name, 0,
+     [{?clause, [], [], [?ATOM(Name)]}]}.
+
+%%% ------------------------------------------------------------------------
+%%% # msg_name/1
+%%% ------------------------------------------------------------------------
+
+f_msg_name(Spec) ->
+    {?function, msg_name, 2, msg_name(Spec)}.
+
+%% Return the empty name for any unknown command to which
+%% DIAMETER_COMMAND_UNSUPPORTED should be replied.
+
+msg_name(Spec) ->
+    lists:flatmap(fun c_msg_name/1,
+                  proplists:get_value(command_codes, Spec, []))
+        ++ [{?clause, [?VAR('_'), ?VAR('_')], [], [?ATOM('')]}].
+
+c_msg_name({Code, Req, Ans}) ->
+    [{?clause, [?INTEGER(Code), ?ATOM(true)],
+      [],
+      [?ATOM(mname(Req))]},
+     {?clause, [?INTEGER(Code), ?ATOM(false)],
+      [],
+      [?ATOM(mname(Ans))]}].
+
+mname({N, _Abbr}) ->
+    N;
+mname(N) ->
+    N.
+
+%%% ------------------------------------------------------------------------
+%%% # msg2rec/1
+%%% ------------------------------------------------------------------------
+
+f_msg2rec(Spec) ->
+    {?function, msg2rec, 1, msg2rec(Spec)}.
+
+msg2rec(Spec) ->
+    Pre = prefix(Spec),
+    Dict = dict:from_list(lists:flatmap(fun msgs/1,
+                                        get_value(command_codes, Spec))),
+    lists:flatmap(fun(T) -> msg2rec(T, Dict, Pre) end,
+                  get_value(messages, Spec))
+        ++ [?UNEXPECTED(1)].
+
+msgs({_Code, Req, Ans}) ->
+    [{mname(Req), Req}, {mname(Ans), Ans}].
+
+msg2rec({N,_,_,_,_}, Dict, Pre) ->
+    c_msg2rec(fetch_names(N, Dict), Pre).
+
+fetch_names(Name, Dict) ->
+    case dict:find(Name, Dict) of
+        {ok, N} ->
+            N;
+        error ->
+            Name
+    end.
+
+c_msg2rec({N,A}, Pre) ->
+    [c_name2rec(N, N, Pre), c_name2rec(A, N, Pre)];
+c_msg2rec(N, Pre) ->
+    [c_name2rec(N, N, Pre)].
+
+%%% ------------------------------------------------------------------------
+%%% # rec2msg/1
+%%% ------------------------------------------------------------------------
+
+f_rec2msg(Spec) ->
+    {?function, rec2msg, 1, rec2msg(Spec)}.
+
+rec2msg(Spec) ->
+    Pre = prefix(Spec),
+    lists:map(fun(T) -> c_rec2msg(T, Pre) end, get_value(messages, Spec))
+        ++ [?UNEXPECTED(1)].
+
+c_rec2msg({N,_,_,_,_}, Pre) ->
+    {?clause, [?ATOM(rec_name(N, Pre))], [], [?ATOM(N)]}.
+
+%%% ------------------------------------------------------------------------
+%%% # name2rec/1
+%%% ------------------------------------------------------------------------
+
+f_name2rec(Spec) ->
+    {?function, name2rec, 1, name2rec(Spec)}.
+
+name2rec(Spec) ->
+    Pre = prefix(Spec),
+    Groups = get_value(grouped, Spec)
+          ++ lists:flatmap(fun avps/1, get_value(import_groups, Spec)),
+    lists:map(fun({N,_,_,_}) -> c_name2rec(N, N, Pre) end, Groups)
+        ++ [{?clause, [?VAR('T')], [], [?CALL(msg2rec, [?VAR('T')])]}].
+
+c_name2rec(Name, Rname, Pre) ->
+    {?clause, [?ATOM(Name)], [], [?ATOM(rec_name(Rname, Pre))]}.
+
+avps({_Mod, Avps}) ->
+    Avps.
+
+%%% ------------------------------------------------------------------------
+%%% # avp_name/1
+%%% ------------------------------------------------------------------------
+
+f_avp_name(Spec) ->
+    {?function, avp_name, 2, avp_name(Spec)}.
+
+%% 3588, 4.1:
+%%
+%%    AVP Code
+%%       The AVP Code, combined with the Vendor-Id field, identifies the
+%%       attribute uniquely.  AVP numbers 1 through 255 are reserved for
+%%       backward compatibility with RADIUS, without setting the Vendor-Id
+%%       field.  AVP numbers 256 and above are used for Diameter, which are
+%%       allocated by IANA (see Section 11.1).
+
+avp_name(Spec) ->
+    Avps = get_value(avp_types, Spec)
+        ++ lists:flatmap(fun avps/1, get_value(import_avps, Spec)),
+    {Vid, _} = orddict:fetch(vendor, Spec),
+    Vs = lists:flatmap(fun({V,Ns}) -> [{N,V} || N <- Ns] end,
+                       get_value(avp_vendor_id, Spec)),
+
+    lists:map(fun(T) -> c_avp_name(T, Vid, Vs) end, Avps)
+        ++ [{?clause, [?VAR('_'), ?VAR('_')], [], [?ATOM('AVP')]}].
+
+c_avp_name({Name, Code, Type, Flags, _Encr}, Vid, Vs) ->
+    c_avp_name({Name, Type},
+               Code,
+               lists:member('V', Flags),
+               Vid,
+               proplists:get_value(Name, Vs)).
+
+c_avp_name(T, Code, false, _, undefined = U) ->
+    {?clause, [?INTEGER(Code), ?ATOM(U)],
+     [],
+     [?TERM(T)]};
+
+c_avp_name(T, Code, true, Vid, V)
+  when is_integer(Vid) ->
+    {?clause, [?INTEGER(Code), ?INTEGER(choose(V == undefined, Vid, V))],
+     [],
+     [?TERM(T)]}.
+
+%%% ------------------------------------------------------------------------
+%%% # avp_arity/2
+%%% ------------------------------------------------------------------------
+
+f_avp_arity(Spec) ->
+    {?function, avp_arity, 2, avp_arity(Spec)}.
+
+avp_arity(Spec) ->
+    Msgs = get_value(messages, Spec),
+    Groups = get_value(grouped, Spec)
+          ++ lists:flatmap(fun avps/1, get_value(import_groups, Spec)),
+    c_avp_arity(Msgs ++ Groups)
+        ++ [{?clause, [?VAR('_'), ?VAR('_')], [], [?INTEGER(0)]}].
+
+c_avp_arity(L)
+  when is_list(L) ->
+    lists:flatmap(fun c_avp_arity/1, L);
+
+c_avp_arity({N,_,_,_,As}) ->
+    c_avp_arity(N,As);
+c_avp_arity({N,_,_,As}) ->
+    c_avp_arity(N,As).
+
+c_avp_arity(Name, Avps) ->
+    lists:map(fun(A) -> c_arity(Name, A) end, Avps).
+
+c_arity(Name, Avp) ->
+    {AvpName, Arity} = avp_info(Avp),
+    {?clause, [?ATOM(Name), ?ATOM(AvpName)], [], [?TERM(Arity)]}.
+
+%%% ------------------------------------------------------------------------
+%%% # avp/3
+%%% ------------------------------------------------------------------------
+
+f_avp(Spec) ->
+    {?function, avp, 3, avp(Spec) ++ [?UNEXPECTED(3)]}.
+
+avp(Spec) ->
+    Native   = get_value(avp_types, Spec),
+    Custom   = get_value(custom_types, Spec),
+    Imported = get_value(import_avps, Spec),
+    avp([{N,T} || {N,_,T,_,_} <- Native], Imported, Custom).
+
+avp(Native, Imported, Custom) ->
+    Dict = orddict:from_list(Native),
+
+    report(native, Dict),
+    report(imported, Imported),
+    report(custom, Custom),
+
+    CustomNames = lists:flatmap(fun({_,Ns}) -> Ns end, Custom),
+
+    lists:map(fun c_base_avp/1,
+              lists:filter(fun({N,_}) ->
+                                   false == lists:member(N, CustomNames)
+                           end,
+                           Native))
+        ++ lists:flatmap(fun c_imported_avp/1, Imported)
+        ++ lists:flatmap(fun(C) -> c_custom_avp(C, Dict) end, Custom).
+
+c_base_avp({AvpName, T}) ->
+    {?clause, [?VAR('T'), ?VAR('Data'), ?ATOM(AvpName)],
+     [],
+     [base_avp(AvpName, T)]}.
+
+base_avp(AvpName, 'Enumerated') ->
+    ?CALL(enumerated_avp, [?VAR('T'), ?ATOM(AvpName), ?VAR('Data')]);
+
+base_avp(AvpName, 'Grouped') ->
+    ?CALL(grouped_avp, [?VAR('T'), ?ATOM(AvpName), ?VAR('Data')]);
+
+base_avp(_, Type) ->
+    ?APPLY(diameter_types, Type, [?VAR('T'), ?VAR('Data')]).
+
+c_imported_avp({Mod, Avps}) ->
+    lists:map(fun(A) -> imported_avp(Mod, A) end, Avps).
+
+imported_avp(_Mod, {AvpName, _, 'Grouped' = T, _, _}) ->
+    c_base_avp({AvpName, T});
+
+imported_avp(Mod, {AvpName, _, _, _, _}) ->
+    {?clause, [?VAR('T'), ?VAR('Data'), ?ATOM(AvpName)],
+     [],
+     [?APPLY(Mod, avp, [?VAR('T'),
+                        ?VAR('Data'),
+                        ?ATOM(AvpName)])]}.
+
+c_custom_avp({Mod, Avps}, Dict) ->
+    lists:map(fun(N) -> custom_avp(Mod, N, orddict:fetch(N, Dict)) end, Avps).
+
+custom_avp(Mod, AvpName, Type) ->
+    {?clause, [?VAR('T'), ?VAR('Data'), ?ATOM(AvpName)],
+     [],
+     [?APPLY(Mod, AvpName, [?VAR('T'), ?ATOM(Type), ?VAR('Data')])]}.
+
+%%% ------------------------------------------------------------------------
+%%% # enumerated_avp/3
+%%% ------------------------------------------------------------------------
+
+f_enumerated_avp(Spec) ->
+    {?function, enumerated_avp, 3, enumerated_avp(Spec) ++ [?UNEXPECTED(3)]}.
+
+enumerated_avp(Spec) ->
+    lists:flatmap(fun c_enumerated_avp/1, get_value(enums, Spec)).
+
+c_enumerated_avp({AvpName, Values}) ->
+    lists:flatmap(fun(V) -> c_enumerated_avp(AvpName, V) end, Values).
+
+c_enumerated_avp(AvpName, {I,_}) ->
+    [{?clause, [?ATOM(decode), ?ATOM(AvpName), ?TERM(<<I:32/integer>>)],
+      [],
+      [?TERM(I)]},
+     {?clause, [?ATOM(encode), ?ATOM(AvpName), ?INTEGER(I)],
+      [],
+      [?TERM(<<I:32/integer>>)]}].
+
+%%% ------------------------------------------------------------------------
+%%% msg_header/1
+%%% ------------------------------------------------------------------------
+
+f_msg_header(Spec) ->
+    {?function, msg_header, 1, msg_header(Spec) ++ [?UNEXPECTED(1)]}.
+
+msg_header(Spec) ->
+    ApplId = orddict:fetch(id, Spec),
+
+    lists:map(fun({M,C,F,_,_}) -> c_msg_header(M, C, F, ApplId) end,
+              get_value(messages, Spec)).
+
+%% Note that any application id in the message header spec is ignored.
+
+c_msg_header(Name, Code, Flags, ApplId) ->
+    {?clause, [?ATOM(Name)],
+     [],
+     [?TERM({Code, encode_msg_flags(Flags), ApplId})]}.
+
+encode_msg_flags(Flags) ->
+    lists:foldl(fun emf/2, 0, Flags).
+
+emf('REQ', N) -> N bor 2#10000000;
+emf('PXY', N) -> N bor 2#01000000;
+emf('ERR', N) -> N bor 2#00100000.
+
+%%% ------------------------------------------------------------------------
+%%% # avp_header/1
+%%% ------------------------------------------------------------------------
+
+f_avp_header(Spec) ->
+    {?function, avp_header, 1, avp_header(Spec) ++ [?UNEXPECTED(1)]}.
+
+avp_header(Spec) ->
+    Native = get_value(avp_types, Spec),
+    Imported = get_value(import_avps, Spec),
+    {Vid, _} = orddict:fetch(vendor, Spec),
+    Vs = lists:flatmap(fun({V,Ns}) -> [{N,V} || N <- Ns] end,
+                       get_value(avp_vendor_id, Spec)),
+
+    lists:flatmap(fun(A) -> c_avp_header({Vid, Vs}, A) end,
+                  Native ++ Imported).
+
+c_avp_header({Vid, Vs}, {Name, Code, _Type, Flags, _Encr}) ->
+    [{?clause, [?ATOM(Name)],
+      [],
+      [?TERM({Code, encode_avp_flags(Flags), vid(Name, Flags, Vs, Vid)})]}];
+
+c_avp_header({_, Vs}, {Mod, Avps}) ->
+    lists:map(fun(A) -> c_avp_header(Vs, Mod, A) end, Avps).
+
+c_avp_header(Vs, Mod, {Name, _, _, Flags, _}) ->
+    Apply = ?APPLY(Mod, avp_header, [?ATOM(Name)]),
+    {?clause, [?ATOM(Name)],
+     [],
+     [case proplists:get_value(Name, Vs) of
+          undefined ->
+              Apply;
+          Vid ->
+              true = lists:member('V', Flags),  %% sanity check
+              ?CALL(setelement, [?INTEGER(3), Apply, ?INTEGER(Vid)])
+      end]}.
+
+encode_avp_flags(Fs) ->
+    lists:foldl(fun eaf/2, 0, Fs).
+
+eaf('V', F) -> 2#10000000 bor F;
+eaf('M', F) -> 2#01000000 bor F;
+eaf('P', F) -> 2#00100000 bor F.
+
+vid(Name, Flags, Vs, Vid) ->
+    v(lists:member('V', Flags), Name, Vs, Vid).
+
+v(true, Name, Vs, Vid) ->
+    proplists:get_value(Name, Vs, Vid);
+v(false, _, _, _) ->
+    undefined.
+
+%%% ------------------------------------------------------------------------
+%%% # empty_value/0
+%%% ------------------------------------------------------------------------
+
+f_empty_value(Spec) ->
+    {?function, empty_value, 1, empty_value(Spec)}.
+
+empty_value(Spec) ->
+    Groups = get_value(grouped, Spec)
+        ++ lists:flatmap(fun avps/1, get_value(import_groups, Spec)),
+    Enums = get_value(enums, Spec)
+        ++ lists:flatmap(fun avps/1, get_value(import_enums, Spec)),
+    lists:map(fun c_empty_value/1, Groups ++ Enums)
+        ++ [{?clause, [?VAR('Name')], [], [?CALL(empty, [?VAR('Name')])]}].
+
+c_empty_value({Name, _, _, _}) ->
+    {?clause, [?ATOM(Name)],
+     [],
+     [?CALL(empty_group, [?ATOM(Name)])]};
+
+c_empty_value({Name, _}) ->
+    {?clause, [?ATOM(Name)],
+     [],
+     [?TERM(<<0:32/integer>>)]}.
+
+%%% ------------------------------------------------------------------------
+%%% # dict/0
+%%% ------------------------------------------------------------------------
+
+f_dict(Spec) ->
+    {?function, dict, 0,
+     [{?clause, [], [], [?TERM(Spec)]}]}.
+
+%%% ------------------------------------------------------------------------
+%%% # gen_hrl/3
+%%% ------------------------------------------------------------------------
+
+gen_hrl(Path, Mod, Spec) ->
+    {ok, Fd} = file:open(Path, [write]),
+
+    {Prefix, MsgRecs, GrpRecs, ImportedGrpRecs}
+        = make_record_forms(Spec),
+
+    file:write(Fd, hrl_header(Mod)),
+
+    forms("Message records",     Fd, MsgRecs),
+    forms("Grouped AVP records", Fd, GrpRecs),
+
+    lists:foreach(fun({M,Fs}) ->
+                          forms("Grouped AVP records from " ++ atom_to_list(M),
+                                Fd,
+                                Fs)
+                  end,
+                  ImportedGrpRecs),
+
+    PREFIX = to_upper(Prefix),
+
+    write("ENUM Macros",
+          Fd,
+          m_enums(PREFIX, false, get_value(enums, Spec))),
+    write("RESULT CODE Macros",
+          Fd,
+          m_enums(PREFIX, false, get_value(result_codes, Spec))),
+
+    lists:foreach(fun({M,Es}) ->
+                          write("ENUM Macros from " ++ atom_to_list(M),
+                                Fd,
+                                m_enums(PREFIX, true, Es))
+                  end,
+                  get_value(import_enums, Spec)),
+
+    file:close(Fd).
+
+forms(_, _, []) ->
+    ok;
+forms(Banner, Fd, Forms) ->
+    write(Banner, Fd, prettypr(Forms)).
+
+write(_, _, []) ->
+    ok;
+write(Banner, Fd, Str) ->
+    banner(Fd, Banner),
+    io:fwrite(Fd, "~s~n", [Str]).
+
+prettypr(Forms) ->
+    erl_prettypr:format(erl_syntax:form_list(Forms)).
+
+banner(Fd, Heading) ->
+    file:write(Fd, banner(Heading)).
+
+banner(Heading) ->
+    ("\n\n"
+     "%%% -------------------------------------------------------\n"
+     "%%% " ++ Heading ++ ":\n"
+     "%%% -------------------------------------------------------\n\n").
+
+z(S) ->
+    string:join(string:tokens(S, "\s\t"), "\s").
+
+m_enums(Prefix, Wrap, Enums) ->
+    lists:map(fun(T) -> m_enum(Prefix, Wrap, T) end, Enums).
+
+m_enum(Prefix, B, {Name, Values}) ->
+    P = Prefix ++ to_upper(Name) ++ "_",
+    lists:map(fun({I,A}) ->
+                      N = ["'", P, to_upper(z(atom_to_list(A))), "'"],
+                      wrap(B,
+                           N,
+                           ["-define(", N, ", ", integer_to_list(I), ").\n"])
+              end,
+              Values).
+
+wrap(true, Name, Def) ->
+    ["-ifndef(", Name, ").\n", Def, "-endif.\n"];
+wrap(false, _, Def) ->
+    Def.
+
+to_upper(A) when is_atom(A) ->
+    to_upper(atom_to_list(A));
+to_upper(S) ->
+    lists:map(fun tu/1, S).
+
+tu(C) when C >= $a, C =< $z ->
+    C + $A - $a;
+tu(C) ->
+    C.
+
+header() ->
+    ("%% -------------------------------------------------------------------\n"
+     "%% This is a generated file.\n"
+     "%% -------------------------------------------------------------------\n"
+     "\n"
+     "%%\n"
+     "%% Copyright (c) Ericsson AB. All rights reserved.\n"
+     "%%\n"
+     "%% The information in this document is the property of Ericsson.\n"
+     "%%\n"
+     "%% Except as specifically authorized in writing by Ericsson, the\n"
+     "%% receiver of this document shall keep the information contained\n"
+     "%% herein confidential and shall protect the same in whole or in\n"
+     "%% part from disclosure and dissemination to third parties.\n"
+     "%%\n"
+     "%% Disclosure and disseminations to the receivers employees shall\n"
+     "%% only be made on a strict need to know basis.\n"
+     "%%\n\n").
+
+hrl_header(Name) ->
+    header() ++ "-hrl_name('" ++ Name ++ ".hrl').\n".
+
+%% avp_info/1
+
+avp_info(Entry) ->  %% {Name, Arity}
+    case Entry of
+        {'<',A,'>'} -> {A, 1};
+        {A}         -> {A, 1};
+        [A]         -> {A, {0,1}};
+        {Q,T} ->
+            {A,_} = avp_info(T),
+            {A, arity(Q)}
+    end.
+
+%% Normalize arity to 1 or {N,X} where N is an integer. A record field
+%% for an AVP is list-valued iff the normalized arity is not 1.
+arity('*' = Inf) -> {0, Inf};
+arity({'*', N})  -> {0, N};
+arity({1,1})     -> 1;
+arity(T)         -> T.
+
+prefix(Spec) ->
+    case orddict:find(prefix, Spec) of
+        {ok, P} ->
+            atom_to_list(P) ++ "_";
+        error ->
+            ""
+    end.
+
+rec_name(Name, Prefix) ->
+    list_to_atom(Prefix ++ atom_to_list(Name)).