%%
%% %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%
%%
%%
%% This module turns a .dia (aka spec) file into the orddict that
%% diameter_codegen.erl in turn morphs into .erl and .hrl files for
%% encode and decode of Diameter messages and AVPs.
%%
-module(diameter_spec_util).
-export([parse/2]).
-define(ERROR(T), erlang:error({T, ?MODULE, ?LINE})).
-define(ATOM, list_to_atom).
%% parse/1
%%
%% Output: orddict()
parse(Path, Opts) ->
put({?MODULE, verbose}, lists:member(verbose, Opts)),
{ok, B} = file:read_file(Path),
Chunks = chunk(B),
Spec = reset(make_spec(Chunks), Opts, [name, prefix, inherits]),
true = groups_defined(Spec), %% sanity checks
true = customs_defined(Spec), %%
Full = import_enums(import_groups(import_avps(insert_codes(Spec), Opts))),
true = enums_defined(Full), %% sanity checks
true = v_flags_set(Spec),
Full.
reset(Spec, Opts, Keys) ->
lists:foldl(fun(K,S) ->
reset([{A,?ATOM(V)} || {A,V} <- Opts, A == K], S)
end,
Spec,
Keys).
reset(L, Spec)
when is_list(L) ->
lists:foldl(fun reset/2, Spec, L);
reset({inherits = Key, '-'}, Spec) ->
orddict:erase(Key, Spec);
reset({inherits = Key, Dict}, Spec) ->
orddict:append(Key, Dict, Spec);
reset({Key, Atom}, Spec) ->
orddict:store(Key, Atom, Spec);
reset(_, Spec) ->
Spec.
%% Optional reports when running verbosely.
report(What, Data) ->
report(get({?MODULE, verbose}), What, Data).
report(true, Tag, Data) ->
io:format("##~n## ~p ~p~n", [Tag, Data]);
report(false, _, _) ->
ok.
%% chunk/1
chunk(B) ->
chunkify(normalize(binary_to_list(B))).
%% normalize/1
%%
%% Replace CR NL by NL, multiple NL by one, tab by space, and strip
%% comments and leading/trailing space from each line. Precludes
%% semicolons being used for any other purpose than comments.
normalize(Str) ->
nh(Str, []).
nh([], Acc) ->
lists:reverse(Acc);
%% Trim leading whitespace.
nh(Str, Acc) ->
nb(trim(Str), Acc).
%% tab -> space
nb([$\t|Rest], Acc) ->
nb(Rest, [$\s|Acc]);
%% CR NL -> NL
nb([$\r,$\n|Rest], Acc) ->
nt(Rest, Acc);
%% Gobble multiple newlines before starting over again.
nb([$\n|Rest], Acc) ->
nt(Rest, Acc);
%% Comment.
nb([$;|Rest], Acc) ->
nb(lists:dropwhile(fun(C) -> C /= $\n end, Rest), Acc);
%% Just an ordinary character. Boring ...
nb([C|Rest], Acc) ->
nb(Rest, [C|Acc]);
nb([] = Str, Acc) ->
nt(Str, Acc).
%% Discard a subsequent newline.
nt(T, [$\n|_] = Acc) ->
nh(T, trim(Acc));
%% Trim whitespace from the end of the line before continuing.
nt(T, Acc) ->
nh(T, [$\n|trim(Acc)]).
trim(S) ->
lists:dropwhile(fun(C) -> lists:member(C, "\s\t") end, S).
%% chunkify/1
%%
%% Split the spec file into pieces delimited by lines starting with
%% @Tag. Returns a list of {Tag, Args, Chunk} where Chunk is the
%% string extending to the next delimiter. Note that leading
%% whitespace has already been stripped.
chunkify(Str) ->
%% Drop characters to the start of the first chunk.
{_, Rest} = split_chunk([$\n|Str]),
chunkify(Rest, []).
chunkify([], Acc) ->
lists:reverse(Acc);
chunkify(Rest, Acc) ->
{H,T} = split_chunk(Rest),
chunkify(T, [split_tag(H) | Acc]).
split_chunk(Str) ->
split_chunk(Str, []).
split_chunk([] = Rest, Acc) ->
{lists:reverse(Acc), Rest};
split_chunk([$@|Rest], [$\n|_] = Acc) ->
{lists:reverse(Acc), Rest};
split_chunk([C|Rest], Acc) ->
split_chunk(Rest, [C|Acc]).
%% Expect a tag and its arguments on a single line.
split_tag(Str) ->
{L, Rest} = get_until($\n, Str),
[{tag, Tag} | Toks] = diameter_spec_scan:parse(L),
{Tag, Toks, trim(Rest)}.
get_until(EndT, L) ->
{H, [EndT | T]} = lists:splitwith(fun(C) -> C =/= EndT end, L),
{H,T}.
%% ------------------------------------------------------------------------
%% make_spec/1
%%
%% Turn chunks into spec.
make_spec(Chunks) ->
lists:foldl(fun(T,A) -> report(chunk, T), chunk(T,A) end,
orddict:new(),
Chunks).
chunk({T, [X], []}, Dict)
when T == name;
T == prefix ->
store(T, atomize(X), Dict);
chunk({id = T, [{number, I}], []}, Dict) ->
store(T, I, Dict);
chunk({vendor = T, [{number, I}, N], []}, Dict) ->
store(T, {I, atomize(N)}, Dict);
%% inherits -> [{Mod, [AvpName, ...]}, ...]
chunk({inherits = T, [_,_|_] = Args, []}, Acc) ->
Mods = [atomize(A) || A <- Args],
append_list(T, [{M,[]} || M <- Mods], Acc);
chunk({inherits = T, [Mod], Body}, Acc) ->
append(T, {atomize(Mod), parse_avp_names(Body)}, Acc);
%% avp_types -> [{AvpName, Code, Type, Flags, Encr}, ...]
chunk({avp_types = T, [], Body}, Acc) ->
store(T, parse_avp_types(Body), Acc);
%% custom_types -> [{Mod, [AvpName, ...]}, ...]
chunk({custom_types = T, [Mod], Body}, Dict) ->
[_|_] = Avps = parse_avp_names(Body),
append(T, {atomize(Mod), Avps}, Dict);
%% messages -> [{MsgName, Code, Type, Appl, Avps}, ...]
chunk({messages = T, [], Body}, Acc) ->
store(T, parse_messages(Body), Acc);
%% grouped -> [{AvpName, Code, Vendor, Avps}, ...]
chunk({grouped = T, [], Body}, Acc) ->
store(T, parse_groups(Body), Acc);
%% avp_vendor_id -> [{Id, [AvpName, ...]}, ...]
chunk({avp_vendor_id = T, [{number, I}], Body}, Dict) ->
[_|_] = Names = parse_avp_names(Body),
append(T, {I, Names}, Dict);
%% enums -> [{AvpName, [{Value, Name}, ...]}, ...]
chunk({enum, [N], Str}, Dict) ->
append(enums, {atomize(N), parse_enums(Str)}, Dict);
%% defines -> [{DefineName, [{Value, Name}, ...]}, ...]
chunk({define, [N], Str}, Dict) ->
append(defines, {atomize(N), parse_enums(Str)}, Dict);
chunk({result_code, [_] = N, Str}, Dict) -> %% backwards compatibility
chunk({define, N, Str}, Dict);
%% commands -> [{Name, Abbrev}, ...]
chunk({commands = T, [], Body}, Dict) ->
store(T, parse_commands(Body), Dict);
chunk(T, _) ->
?ERROR({unknown_tag, T}).
store(Key, Value, Dict) ->
error == orddict:find(Key, Dict) orelse ?ERROR({duplicate, Key}),
orddict:store(Key, Value, Dict).
append(Key, Value, Dict) ->
orddict:append(Key, Value, Dict).
append_list(Key, Values, Dict) ->
orddict:append_list(Key, Values, Dict).
atomize({tag, T}) ->
T;
atomize({name, T}) ->
?ATOM(T).
get_value(Keys, Spec)
when is_list(Keys) ->
[get_value(K, Spec) || K <- Keys];
get_value(Key, Spec) ->
proplists:get_value(Key, Spec, []).
%% ------------------------------------------------------------------------
%% enums_defined/1
%% groups_defined/1
%% customs_defined/1
%%
%% Ensure that every local enum/grouped/custom is defined as an avp
%% with an appropriate type.
enums_defined(Spec) ->
Avps = get_value(avp_types, Spec),
Import = get_value(import_enums, Spec),
lists:all(fun({N,_}) ->
true = enum_defined(N, Avps, Import)
end,
get_value(enums, Spec)).
enum_defined(Name, Avps, Import) ->
case lists:keyfind(Name, 1, Avps) of
{Name, _, 'Enumerated', _, _} ->
true;
{Name, _, T, _, _} ->
?ERROR({avp_has_wrong_type, Name, 'Enumerated', T});
false ->
lists:any(fun({_,Is}) -> lists:keymember(Name, 1, Is) end, Import)
orelse ?ERROR({avp_not_defined, Name, 'Enumerated'})
end.
%% Note that an AVP is imported only if referenced by a message or
%% grouped AVP, so the final branch will fail if an enum definition is
%% extended without this being the case.
groups_defined(Spec) ->
Avps = get_value(avp_types, Spec),
lists:all(fun({N,_,_,_}) -> true = group_defined(N, Avps) end,
get_value(grouped, Spec)).
group_defined(Name, Avps) ->
case lists:keyfind(Name, 1, Avps) of
{Name, _, 'Grouped', _, _} ->
true;
{Name, _, T, _, _} ->
?ERROR({avp_has_wrong_type, Name, 'Grouped', T});
false ->
?ERROR({avp_not_defined, Name, 'Grouped'})
end.
customs_defined(Spec) ->
Avps = get_value(avp_types, Spec),
lists:all(fun(A) -> true = custom_defined(A, Avps) end,
lists:flatmap(fun last/1, get_value(custom_types, Spec))).
custom_defined(Name, Avps) ->
case lists:keyfind(Name, 1, Avps) of
{Name, _, T, _, _} when T == 'Grouped';
T == 'Enumerated' ->
?ERROR({avp_has_invalid_custom_type, Name, T});
{Name, _, _, _, _} ->
true;
false ->
?ERROR({avp_not_defined, Name})
end.
last({_,Xs}) -> Xs.
%% ------------------------------------------------------------------------
%% v_flags_set/1
v_flags_set(Spec) ->
Avps = get_value(avp_types, Spec)
++ lists:flatmap(fun last/1, get_value(import_avps, Spec)),
Vs = lists:flatmap(fun last/1, get_value(avp_vendor_id, Spec)),
lists:all(fun(N) -> vset(N, Avps) end, Vs).
vset(Name, Avps) ->
A = lists:keyfind(Name, 1, Avps),
false == A andalso ?ERROR({avp_not_defined, Name}),
{Name, _Code, _Type, Flags, _Encr} = A,
lists:member('V', Flags) orelse ?ERROR({v_flag_not_set, A}).
%% ------------------------------------------------------------------------
%% insert_codes/1
insert_codes(Spec) ->
[Msgs, Cmds] = get_value([messages, commands], Spec),
%% Code -> [{Name, Flags}, ...]
Dict = lists:foldl(fun({N,C,Fs,_,_}, D) -> dict:append(C,{N,Fs},D) end,
dict:new(),
Msgs),
%% list() of {Code, {ReqName, ReqAbbr}, {AnsName, AnsAbbr}}
%% If the name and abbreviation are the same then the 2-tuples
%% are replaced by the common atom()-valued name.
Codes = dict:fold(fun(C,Ns,A) -> [make_code(C, Ns, Cmds) | A] end,
[],
dict:erase(-1, Dict)), %% answer-message
orddict:store(command_codes, Codes, Spec).
make_code(Code, [_,_] = Ns, Cmds) ->
{Req, Ans} = make_names(Ns, lists:map(fun({_,Fs}) ->
lists:member('REQ', Fs)
end,
Ns)),
{Code, abbrev(Req, Cmds), abbrev(Ans, Cmds)};
make_code(Code, Cs, _) ->
?ERROR({missing_request_or_answer, Code, Cs}).
%% 3.3. Diameter Command Naming Conventions
%%
%% Diameter command names typically includes one or more English words
%% followed by the verb Request or Answer. Each English word is
%% delimited by a hyphen. A three-letter acronym for both the request
%% and answer is also normally provided.
make_names([{Rname,_},{Aname,_}], [true, false]) ->
{Rname, Aname};
make_names([{Aname,_},{Rname,_}], [false, true]) ->
{Rname, Aname};
make_names([_,_] = Names, _) ->
?ERROR({inconsistent_command_flags, Names}).
abbrev(Name, Cmds) ->
case abbr(Name, get_value(Name, Cmds)) of
Name ->
Name;
Abbr ->
{Name, Abbr}
end.
%% No explicit abbreviation: construct.
abbr(Name, []) ->
?ATOM(abbr(string:tokens(atom_to_list(Name), "-")));
%% Abbreviation was specified.
abbr(_Name, Abbr) ->
Abbr.
%% No hyphens: already abbreviated.
abbr([Abbr]) ->
Abbr;
%% XX-Request/Answer ==> XXR/XXA
abbr([[_,_] = P, T])
when T == "Request";
T == "Answer" ->
P ++ [hd(T)];
%% XXX-...-YYY-Request/Answer ==> X...YR/X...YA
abbr([_,_|_] = L) ->
lists:map(fun erlang:hd/1, L).
%% ------------------------------------------------------------------------
%% import_avps/2
import_avps(Spec, Options) ->
Msgs = get_value(messages, Spec),
Groups = get_value(grouped, Spec),
%% Messages and groups require AVP's referenced by them.
NeededAvps
= ordsets:from_list(lists:flatmap(fun({_,_,_,_,As}) ->
[avp_name(A) || A <- As]
end,
Msgs)
++ lists:flatmap(fun({_,_,_,As}) ->
[avp_name(A) || A <- As]
end,
Groups)),
MissingAvps = missing_avps(NeededAvps, Spec),
report(needed, NeededAvps),
report(missing, MissingAvps),
Import = inherit(get_value(inherits, Spec), Options),
report(imported, Import),
ImportedAvps = lists:map(fun({N,_,_,_,_}) -> N end,
lists:flatmap(fun last/1, Import)),
Unknown = MissingAvps -- ImportedAvps,
[] == Unknown orelse ?ERROR({undefined_avps, Unknown}),
orddict:store(import_avps, Import, orddict:erase(inherits, Spec)).
%% missing_avps/2
%%
%% Given a list of AVP names and parsed spec, return the list of
%% AVP's that aren't defined in this spec.
missing_avps(NeededNames, Spec) ->
Avps = get_value(avp_types, Spec),
Groups = lists:map(fun({N,_,_,As}) ->
{N, [avp_name(A) || A <- As]}
end,
get_value(grouped, Spec)),
Names = ordsets:from_list(['AVP' | lists:map(fun({N,_,_,_,_}) -> N end,
Avps)]),
missing_avps(NeededNames, [], {Names, Groups}).
avp_name({'<',A,'>'}) -> A;
avp_name({A}) -> A;
avp_name([A]) -> A;
avp_name({_, A}) -> avp_name(A).
missing_avps(NeededNames, MissingNames, {Names, _} = T) ->
missing(ordsets:filter(fun(N) -> lists:member(N, NeededNames) end, Names),
ordsets:union(NeededNames, MissingNames),
T).
%% Nothing found locally.
missing([], MissingNames, _) ->
MissingNames;
%% Or not. Keep looking for for the AVP's needed by the found AVP's of
%% type Grouped.
missing(FoundNames, MissingNames, {_, Groups} = T) ->
NeededNames = lists:flatmap(fun({N,As}) ->
choose(lists:member(N, FoundNames), As, [])
end,
Groups),
missing_avps(ordsets:from_list(NeededNames),
ordsets:subtract(MissingNames, FoundNames),
T).
%% inherit/2
inherit(Inherits, Options) ->
Dirs = [D || {include, D} <- Options] ++ ["."],
lists:foldl(fun(T,A) -> find_avps(T, A, Dirs) end, [], Inherits).
find_avps({Mod, AvpNames}, Acc, Path) ->
report(inherit_from, Mod),
Avps = avps_from_beam(find_beam(Mod, Path), Mod), %% could be empty
[{Mod, lists:sort(find_avps(AvpNames, Avps))} | Acc].
find_avps([], Avps) ->
Avps;
find_avps(Names, Avps) ->
lists:filter(fun({N,_,_,_,_}) -> lists:member(N, Names) end, Avps).
%% find_beam/2
find_beam(Mod, Dirs)
when is_atom(Mod) ->
find_beam(atom_to_list(Mod), Dirs);
find_beam(Mod, Dirs) ->
Beam = Mod ++ code:objfile_extension(),
case try_path(Dirs, Beam) of
{value, Path} ->
Path;
false ->
?ERROR({beam_not_on_path, Beam, Dirs})
end.
try_path([D|Ds], Fname) ->
Path = filename:join(D, Fname),
case file:read_file_info(Path) of
{ok, _} ->
{value, Path};
_ ->
try_path(Ds, Fname)
end;
try_path([], _) ->
false.
%% avps_from_beam/2
avps_from_beam(Path, Mod) ->
report(beam, Path),
ok = load_module(code:is_loaded(Mod), Mod, Path),
orddict:fetch(avp_types, Mod:dict()).
load_module(false, Mod, Path) ->
R = filename:rootname(Path, code:objfile_extension()),
{module, Mod} = code:load_abs(R),
ok;
load_module({file, _}, _, _) ->
ok.
choose(true, X, _) -> X;
choose(false, _, X) -> X.
%% ------------------------------------------------------------------------
%% import_groups/1
%% import_enums/1
%%
%% For each inherited module, store the content of imported AVP's of
%% type grouped/enumerated in a new key.
import_groups(Spec) ->
orddict:store(import_groups, import(grouped, Spec), Spec).
import_enums(Spec) ->
orddict:store(import_enums, import(enums, Spec), Spec).
import(Key, Spec) ->
lists:flatmap(fun(T) -> import_key(Key, T) end,
get_value(import_avps, Spec)).
import_key(Key, {Mod, Avps}) ->
Imports = lists:flatmap(fun(T) ->
choose(lists:keymember(element(1,T),
1,
Avps),
[T],
[])
end,
get_value(Key, Mod:dict())),
if Imports == [] ->
[];
true ->
[{Mod, Imports}]
end.
%% ------------------------------------------------------------------------
%% parse_enums/1
%%
%% Enums are specified either as the integer value followed by the
%% name or vice-versa. In the former case the name of the enum is
%% taken to be the string up to the end of line, which may contain
%% whitespace. In the latter case the integer may be parenthesized,
%% specified in hex and followed by an inline comment. This is
%% historical and will likely be changed to require a precise input
%% format.
%%
%% Output: list() of {integer(), atom()}
parse_enums(Str) ->
lists:flatmap(fun(L) -> parse_enum(trim(L)) end, string:tokens(Str, "\n")).
parse_enum([]) ->
[];
parse_enum(Str) ->
REs = [{"^(0[xX][0-9A-Fa-f]+|[0-9]+)\s+(.*?)\s*$", 1, 2},
{"^(.+?)\s+(0[xX][0-9A-Fa-f]+|[0-9]+)(\s+.*)?$", 2, 1},
{"^(.+?)\s+\\((0[xX][0-9A-Fa-f]+|[0-9]+)\\)(\s+.*)?$", 2, 1}],
parse_enum(Str, REs).
parse_enum(Str, REs) ->
try lists:foreach(fun(R) -> enum(Str, R) end, REs) of
ok ->
?ERROR({bad_enum, Str})
catch
throw: {enum, T} ->
[T]
end.
enum(Str, {Re, I, N}) ->
case re:run(Str, Re, [{capture, all_but_first, list}]) of
{match, Vs} ->
T = list_to_tuple(Vs),
throw({enum, {to_int(element(I,T)), ?ATOM(element(N,T))}});
nomatch ->
ok
end.
to_int([$0,X|Hex])
when X == $x;
X == $X ->
{ok, [I], _} = io_lib:fread("~#", "16#" ++ Hex),
I;
to_int(I) ->
list_to_integer(I).
%% ------------------------------------------------------------------------
%% parse_messages/1
%%
%% Parse according to the ABNF for message specifications in 3.2 of
%% RFC 3588 (shown below). We require all message and AVP names to
%% start with a digit or uppercase character, except for the base
%% answer-message, which is treated as a special case. Allowing names
%% that start with a digit is more than the RFC specifies but the name
%% doesn't affect what's sent over the wire. (Certains 3GPP standards
%% use names starting with a digit. eg 3GPP-Charging-Id in TS32.299.)
%%
%% Sadly, not even the RFC follows this grammar. In particular, except
%% in the example in 3.2, it wraps each command-name in angle brackets
%% ('<' '>') which makes parsing a sequence of specifications require
%% lookahead: after 'optional' avps have been parsed, it's not clear
%% whether a '<' is a 'fixed' or whether it's the start of a
%% subsequent message until we see whether or not '::=' follows the
%% closing '>'. Require the grammar as specified.
%%
%% Output: list of {Name, Code, Flags, ApplId, Avps}
%%
%% Name = atom()
%% Code = integer()
%% Flags = integer()
%% ApplId = [] | [integer()]
%% Avps = see parse_avps/1
parse_messages(Str) ->
p_cmd(trim(Str), []).
%% command-def = command-name "::=" diameter-message
%%
%% command-name = diameter-name
%%
%% diameter-name = ALPHA *(ALPHA / DIGIT / "-")
%%
%% diameter-message = header [ *fixed] [ *required] [ *optional]
%% [ *fixed]
%%
%% header = "<" Diameter-Header:" command-id
%% [r-bit] [p-bit] [e-bit] [application-id]">"
%%
%% The header spec (and example that follows it) is slightly mangled
%% and, given the examples in the RFC should as follows:
%%
%% header = "<" "Diameter Header:" command-id
%% [r-bit] [p-bit] [e-bit] [application-id]">"
%%
%% This is what's required/parsed below, modulo whitespace. This is
%% also what's specified in the current draft standard at
%% http://ftp.ietf.org/drafts/wg/dime.
%%
%% Note that the grammar specifies the order fixed, required,
%% optional. In practise there seems to be little difference between
%% the latter two since qualifiers can be used to change the
%% semantics. For example 1*[XXX] and *1{YYY} specify 1 or more of the
%% optional avp XXX and 0 or 1 of the required avp YYY, making the
%% iotional avp required and the required avp optional. The current
%% draft addresses this somewhat by requiring that min for a qualifier
%% on an optional avp must be 0 if present. It doesn't say anything
%% about required avps however, so specifying a min of 0 would still
%% be possible. The draft also does away with the trailing *fixed.
%%
%% What will be parsed here will treat required and optional
%% interchangeably. That is. only require that required/optional
%% follow and preceed fixed, not that optional avps must follow
%% required ones. We already have several specs for which this parsing
%% is necessary and there seems to be no harm in accepting it.
p_cmd("", Acc) ->
lists:reverse(Acc);
p_cmd(Str, Acc) ->
{Next, Rest} = split_def(Str),
report(command, Next),
p_cmd(Rest, [p_cmd(Next) | Acc]).
p_cmd("answer-message" ++ Str) ->
p_header([{name, 'answer-message'} | diameter_spec_scan:parse(Str)]);
p_cmd(Str) ->
p_header(diameter_spec_scan:parse(Str)).
%% p_header/1
p_header(['<', {name, _} = N, '>' | Toks]) ->
p_header([N | Toks]);
p_header([{name, 'answer-message' = N}, '::=',
'<', {name, "Diameter"}, {name, "Header"}, ':', {tag, code},
',', {name, "ERR"}, '[', {name, "PXY"}, ']', '>'
| Toks]) ->
{N, -1, ['ERR', 'PXY'], [], parse_avps(Toks)};
p_header([{name, Name}, '::=',
'<', {name, "Diameter"}, {name, "Header"}, ':', {number, Code}
| Toks]) ->
{Flags, Rest} = p_flags(Toks),
{ApplId, [C|_] = R} = p_appl(Rest),
'>' == C orelse ?ERROR({invalid_flag, {Name, Code, Flags, ApplId}, R}),
{?ATOM(Name), Code, Flags, ApplId, parse_avps(tl(R))};
p_header(Toks) ->
?ERROR({invalid_header, Toks}).
%% application-id = 1*DIGIT
%%
%% command-id = 1*DIGIT
%% ; The Command Code assigned to the command
%%
%% r-bit = ", REQ"
%% ; If present, the 'R' bit in the Command
%% ; Flags is set, indicating that the message
%% ; is a request, as opposed to an answer.
%%
%% p-bit = ", PXY"
%% ; If present, the 'P' bit in the Command
%% ; Flags is set, indicating that the message
%% ; is proxiable.
%%
%% e-bit = ", ERR"
%% ; If present, the 'E' bit in the Command
%% ; Flags is set, indicating that the answer
%% ; message contains a Result-Code AVP in
%% ; the "protocol error" class.
p_flags(Toks) ->
lists:foldl(fun p_flags/2, {[], Toks}, ["REQ", "PXY", "ERR"]).
p_flags(N, {Acc, [',', {name, N} | Toks]}) ->
{[?ATOM(N) | Acc], Toks};
p_flags(_, T) ->
T.
%% The RFC doesn't specify ',' before application-id but this seems a
%% bit inconsistent. Accept a comma if it exists.
p_appl([',', {number, I} | Toks]) ->
{[I], Toks};
p_appl([{number, I} | Toks]) ->
{[I], Toks};
p_appl(Toks) ->
{[], Toks}.
%% parse_avps/1
%%
%% Output: list() of Avp | {Qual, Avp}
%%
%% Qual = '*' | {Min, '*'} | {'*', Max} | {Min, Max}
%% Avp = {'<', Name, '>'} | {Name} | [Name]
%%
%% Min, Max = integer() >= 0
parse_avps(Toks) ->
p_avps(Toks, ['<', '|', '<'], []).
%% The list corresponds to the delimiters expected at the front, middle
%% and back of the avp specification, '|' representing '{' and '['.
%% fixed = [qual] "<" avp-spec ">"
%% ; Defines the fixed position of an AVP
%%
%% required = [qual] "{" avp-spec "}"
%% ; The AVP MUST be present and can appear
%% ; anywhere in the message.
%%
%% optional = [qual] "[" avp-name "]"
%% ; The avp-name in the 'optional' rule cannot
%% ; evaluate to any AVP Name which is included
%% ; in a fixed or required rule. The AVP can
%% ; appear anywhere in the message.
%%
%% qual = [min] "*" [max]
%% ; See ABNF conventions, RFC 2234 Section 6.6.
%% ; The absence of any qualifiers depends on whether
%% ; it precedes a fixed, required, or optional
%% ; rule. If a fixed or required rule has no
%% ; qualifier, then exactly one such AVP MUST
%% ; be present. If an optional rule has no
%% ; qualifier, then 0 or 1 such AVP may be
%% ; present.
%% ;
%% ; NOTE: "[" and "]" have a different meaning
%% ; than in ABNF (see the optional rule, above).
%% ; These braces cannot be used to express
%% ; optional fixed rules (such as an optional
%% ; ICV at the end). To do this, the convention
%% ; is '0*1fixed'.
%%
%% min = 1*DIGIT
%% ; The minimum number of times the element may
%% ; be present. The default value is zero.
%%
%% max = 1*DIGIT
%% ; The maximum number of times the element may
%% ; be present. The default value is infinity. A
%% ; value of zero implies the AVP MUST NOT be
%% ; present.
%%
%% avp-spec = diameter-name
%% ; The avp-spec has to be an AVP Name, defined
%% ; in the base or extended Diameter
%% ; specifications.
%%
%% avp-name = avp-spec / "AVP"
%% ; The string "AVP" stands for *any* arbitrary
%% ; AVP Name, which does not conflict with the
%% ; required or fixed position AVPs defined in
%% ; the command code definition.
%%
p_avps([], _, Acc) ->
lists:reverse(Acc);
p_avps(Toks, Delim, Acc) ->
{Qual, Rest} = p_qual(Toks),
{Avp, R, D} = p_avp(Rest, Delim),
T = if Qual == false ->
Avp;
true ->
{Qual, Avp}
end,
p_avps(R, D, [T | Acc]).
p_qual([{number, Min}, '*', {number, Max} | Toks]) ->
{{Min, Max}, Toks};
p_qual([{number, Min}, '*' = Max | Toks]) ->
{{Min, Max}, Toks};
p_qual(['*' = Min, {number, Max} | Toks]) ->
{{Min, Max}, Toks};
p_qual(['*' = Q | Toks]) ->
{Q, Toks};
p_qual(Toks) ->
{false, Toks}.
p_avp([B, {name, Name}, E | Toks], [_|_] = Delim) ->
{avp(B, ?ATOM(Name), E),
Toks,
delim(choose(B == '<', B, '|'), Delim)};
p_avp(Toks, Delim) ->
?ERROR({invalid_avp, Toks, Delim}).
avp('<' = B, Name, '>' = E) ->
{B, Name, E};
avp('{', Name, '}') ->
{Name};
avp('[', Name, ']') ->
[Name];
avp(B, Name, E) ->
?ERROR({invalid_avp, B, Name, E}).
delim(B, D) ->
if B == hd(D) -> D; true -> tl(D) end.
%% split_def/1
%%
%% Strip one command definition off head of a string.
split_def(Str) ->
sdh(Str, []).
%% Look for the "::=" starting off the definition.
sdh("", _) ->
?ERROR({missing, '::='});
sdh("::=" ++ Rest, Acc) ->
sdb(Rest, [$=,$:,$:|Acc]);
sdh([C|Rest], Acc) ->
sdh(Rest, [C|Acc]).
%% Look for the "::=" starting off the following definition.
sdb("::=" ++ _ = Rest, Acc) ->
sdt(trim(Acc), Rest);
sdb("" = Rest, Acc) ->
sd(Acc, Rest);
sdb([C|Rest], Acc) ->
sdb(Rest, [C|Acc]).
%% Put name characters of the subsequent specification back into Rest.
sdt([C|Acc], Rest)
when C /= $\n, C /= $\s ->
sdt(Acc, [C|Rest]);
sdt(Acc, Rest) ->
sd(Acc, Rest).
sd(Acc, Rest) ->
{trim(lists:reverse(Acc)), Rest}.
%% Note that Rest is already trimmed of leading space.
%% ------------------------------------------------------------------------
%% parse_groups/1
%%
%% Parse according to the ABNF for message specifications in 4.4 of
%% RFC 3588 (shown below). Again, allow names starting with a digit
%% and also require "AVP Header" without "-" since this is what
%% the RFC uses in all examples.
%%
%% Output: list of {Name, Code, Vendor, Avps}
%%
%% Name = atom()
%% Code = integer()
%% Vendor = [] | [integer()]
%% Avps = see parse_avps/1
parse_groups(Str) ->
p_group(trim(Str), []).
%% grouped-avp-def = name "::=" avp
%%
%% name-fmt = ALPHA *(ALPHA / DIGIT / "-")
%%
%% name = name-fmt
%% ; The name has to be the name of an AVP,
%% ; defined in the base or extended Diameter
%% ; specifications.
%%
%% avp = header [ *fixed] [ *required] [ *optional]
%% [ *fixed]
%%
%% header = "<" "AVP-Header:" avpcode [vendor] ">"
%%
%% avpcode = 1*DIGIT
%% ; The AVP Code assigned to the Grouped AVP
%%
%% vendor = 1*DIGIT
%% ; The Vendor-ID assigned to the Grouped AVP.
%% ; If absent, the default value of zero is
%% ; used.
p_group("", Acc) ->
lists:reverse(Acc);
p_group(Str, Acc) ->
{Next, Rest} = split_def(Str),
report(group, Next),
p_group(Rest, [p_group(diameter_spec_scan:parse(Next)) | Acc]).
p_group([{name, Name}, '::=', '<', {name, "AVP"}, {name, "Header"},
':', {number, Code}
| Toks]) ->
{Id, [C|_] = R} = p_vendor(Toks),
C == '>' orelse ?ERROR({invalid_group_header, R}),
{?ATOM(Name), Code, Id, parse_avps(tl(R))};
p_group(Toks) ->
?ERROR({invalid_group, Toks}).
p_vendor([{number, I} | Toks]) ->
{[I], Toks};
p_vendor(Toks) ->
{[], Toks}.
%% ------------------------------------------------------------------------
%% parse_avp_names/1
parse_avp_names(Str) ->
[p_name(N) || N <- diameter_spec_scan:parse(Str)].
p_name({name, N}) ->
?ATOM(N);
p_name(T) ->
?ERROR({invalid_avp_name, T}).
%% ------------------------------------------------------------------------
%% parse_avp_types/1
%%
%% Output: list() of {Name, Code, Type, Flags, Encr}
parse_avp_types(Str) ->
p_avp_types(Str, []).
p_avp_types(Str, Acc) ->
p_type(diameter_spec_scan:split(Str, 3), Acc).
p_type({[],[]}, Acc) ->
lists:reverse(Acc);
p_type({[{name, Name}, {number, Code}, {name, Type}], Str}, Acc) ->
{Flags, Encr, Rest} = try
p_avp_flags(trim(Str), [])
catch
throw: {?MODULE, Reason} ->
?ERROR({invalid_avp_type, Reason})
end,
p_avp_types(Rest, [{?ATOM(Name), Code, ?ATOM(type(Type)), Flags, Encr}
| Acc]);
p_type(T, _) ->
?ERROR({invalid_avp_type, T}).
p_avp_flags([C|Str], Acc)
when C == $M;
C == $P;
C == $V ->
p_avp_flags(Str, [?ATOM([C]) | Acc]);
%% Could support lowercase here if there's a use for distinguishing
%% between Must and Should in the future in deciding whether or not
%% to set a flag.
p_avp_flags([$-|Str], Acc) ->
%% Require encr on same line as flags if specified.
{H,T} = lists:splitwith(fun(C) -> C /= $\n end, Str),
{[{name, [$X|X]} | Toks], Rest} = diameter_spec_scan:split([$X|H], 2),
"" == X orelse throw({?MODULE, {invalid_avp_flag, Str}}),
Encr = case Toks of
[] ->
"-";
[{_, E}] ->
(E == "Y" orelse E == "N")
orelse throw({?MODULE, {invalid_encr, E}}),
E
end,
Flags = ordsets:from_list(lists:reverse(Acc)),
{Flags, ?ATOM(Encr), Rest ++ T};
p_avp_flags(Str, Acc) ->
p_avp_flags([$-|Str], Acc).
type("DiamIdent") -> "DiameterIdentity"; %% RFC 3588
type("DiamURI") -> "DiameterURI"; %% RFC 3588
type("IPFltrRule") -> "IPFilterRule"; %% RFC 4005
type("QoSFltrRule") -> "QoSFilterRule"; %% RFC 4005
type(N)
when N == "OctetString";
N == "Integer32";
N == "Integer64";
N == "Unsigned32";
N == "Unsigned64";
N == "Float32";
N == "Float64";
N == "Grouped";
N == "Enumerated";
N == "Address";
N == "Time";
N == "UTF8String";
N == "DiameterIdentity";
N == "DiameterURI";
N == "IPFilterRule";
N == "QoSFilterRule" ->
N;
type(N) ->
?ERROR({invalid_avp_type, N}).
%% ------------------------------------------------------------------------
%% parse_commands/1
parse_commands(Str) ->
p_abbr(diameter_spec_scan:parse(Str), []).
p_abbr([{name, Name}, {name, Abbrev} | Toks], Acc)
when length(Abbrev) < length(Name) ->
p_abbr(Toks, [{?ATOM(Name), ?ATOM(Abbrev)} | Acc]);
p_abbr([], Acc) ->
lists:reverse(Acc);
p_abbr(T, _) ->
?ERROR({invalid_command, T}).