%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2010-2013. 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 file contains code that's included by encode/decode modules
%% generated by diameter_codegen.erl. This code does most of the work, the
%% generated code being kept simple.
%%
-define(THROW(T), throw({?MODULE, T})).
-type parent_name() :: atom(). %% parent = Message or AVP
-type parent_record() :: tuple(). %%
-type avp_name() :: atom().
-type avp_record() :: tuple().
-type avp_values() :: [{avp_name(), term()}].
-type non_grouped_avp() :: #diameter_avp{}.
-type grouped_avp() :: nonempty_improper_list(#diameter_avp{}, [avp()]).
-type avp() :: non_grouped_avp() | grouped_avp().
%% ---------------------------------------------------------------------------
%% # encode_avps/2
%% ---------------------------------------------------------------------------
-spec encode_avps(parent_name(), parent_record() | avp_values())
-> binary()
| no_return().
encode_avps(Name, Vals)
when is_list(Vals) ->
encode_avps(Name, '#set-'(Vals, newrec(Name)));
encode_avps(Name, Rec) ->
try
list_to_binary(encode(Name, Rec))
catch
throw: {?MODULE, Reason} ->
diameter_lib:log({encode, error},
?MODULE,
?LINE,
{Reason, Name, Rec}),
erlang:error(list_to_tuple(Reason ++ [Name]));
error: Reason ->
Stack = erlang:get_stacktrace(),
diameter_lib:log({encode, failure},
?MODULE,
?LINE,
{Reason, Name, Rec, Stack}),
erlang:error({encode_failure, Reason, Name, Stack})
end.
%% encode/2
encode(Name, Rec) ->
lists:flatmap(fun(A) -> encode(Name, A, '#get-'(A, Rec)) end,
'#info-'(element(1, Rec), fields)).
%% encode/3
encode(Name, AvpName, Values) ->
e(Name, AvpName, avp_arity(Name, AvpName), Values).
%% e/4
e(_, AvpName, 1, undefined) ->
?THROW([mandatory_avp_missing, AvpName]);
e(Name, AvpName, 1, Value) ->
e(Name, AvpName, [Value]);
e(_, _, {0,_}, []) ->
[];
e(_, AvpName, _, T)
when not is_list(T) ->
?THROW([repeated_avp_as_non_list, AvpName, T]);
e(_, AvpName, {Min, _}, L)
when length(L) < Min ->
?THROW([repeated_avp_insufficient_arity, AvpName, Min, L]);
e(_, AvpName, {_, Max}, L)
when Max < length(L) ->
?THROW([repeated_avp_excessive_arity, AvpName, Max, L]);
e(Name, AvpName, _, Values) ->
e(Name, AvpName, Values).
%% e/3
e(Name, 'AVP', Values) ->
[pack_AVP(Name, A) || A <- Values];
e(_, AvpName, Values) ->
e(AvpName, Values).
%% e/2
e(AvpName, Values) ->
H = avp_header(AvpName),
[diameter_codec:pack_avp(H, avp(encode, V, AvpName)) || V <- Values].
%% pack_AVP/2
%% No value: assume AVP data is already encoded. The normal case will
%% be when this is passed back from #diameter_packet.errors as a
%% consequence of a failed decode. Any AVP can be encoded this way
%% however, which side-steps any arity checks for known AVP's and
%% could potentially encode something unfortunate.
pack_AVP(_, #diameter_avp{value = undefined} = A) ->
diameter_codec:pack_avp(A);
%% Missing name for value encode.
pack_AVP(_, #diameter_avp{name = N, value = V})
when N == undefined;
N == 'AVP' ->
?THROW([value_with_nameless_avp, N, V]);
%% Or not. Ensure that 'AVP' is the appropriate field. Note that if we
%% don't know this AVP at all then the encode will fail.
pack_AVP(Name, #diameter_avp{name = AvpName,
value = Data}) ->
0 == avp_arity(Name, AvpName)
orelse ?THROW([known_avp_as_AVP, Name, AvpName, Data]),
e(AvpName, [Data]).
%% ---------------------------------------------------------------------------
%% # decode_avps/2
%% ---------------------------------------------------------------------------
-spec decode_avps(parent_name(), [#diameter_avp{}])
-> {parent_record(), [avp()], Failed}
when Failed :: [{5000..5999, #diameter_avp{}}].
decode_avps(Name, Recs) ->
d_rc(Name, lists:foldl(fun(T,A) -> decode(Name, T, A) end,
{[], {newrec(Name), []}},
Recs)).
newrec(Name) ->
'#new-'(name2rec(Name)).
%% No errors so far: keep looking.
d_rc(Name, {Avps, {Rec, [] = Failed}}) ->
try
true = have_required_avps(Rec, Name),
{Rec, Avps, Failed}
catch
throw: {?MODULE, {AvpName, Reason}} ->
diameter_lib:log({decode, error},
?MODULE,
?LINE,
{AvpName, Reason, Rec}),
{Rec, Avps, [{5005, empty_avp(AvpName)}]}
end;
%% 3588:
%%
%% DIAMETER_MISSING_AVP 5005
%% The request did not contain an AVP that is required by the Command
%% Code definition. If this value is sent in the Result-Code AVP, a
%% Failed-AVP AVP SHOULD be included in the message. The Failed-AVP
%% AVP MUST contain an example of the missing AVP complete with the
%% Vendor-Id if applicable. The value field of the missing AVP
%% should be of correct minimum length and contain zeroes.
%% Or not. Only need to report the first error so look no further.
d_rc(_, {Avps, {Rec, Failed}}) ->
{Rec, Avps, lists:reverse(Failed)}.
%% empty_avp/1
empty_avp(Name) ->
{Code, Flags, VId} = avp_header(Name),
{Name, Type} = avp_name(Code, VId),
#diameter_avp{name = Name,
code = Code,
vendor_id = VId,
is_mandatory = 0 /= (Flags band 2#01000000),
need_encryption = 0 /= (Flags band 2#00100000),
data = empty_value(Name),
type = Type}.
%% have_required_avps/2
have_required_avps(Rec, Name) ->
lists:foreach(fun(F) -> hra(Name, F, Rec) end,
'#info-'(element(1, Rec), fields)),
true.
hra(Name, AvpName, Rec) ->
Arity = avp_arity(Name, AvpName),
hra(Arity, '#get-'(AvpName, Rec))
orelse ?THROW({AvpName, {insufficient_arity, Arity}}).
%% Maximum arities have already been checked in building the record.
hra({Min, _}, L) ->
Min =< length(L);
hra(N, V) ->
N /= 1 orelse V /= undefined.
%% 3588, ch 7:
%%
%% The Result-Code AVP describes the error that the Diameter node
%% encountered in its processing. In case there are multiple errors,
%% the Diameter node MUST report only the first error it encountered
%% (detected possibly in some implementation dependent order). The
%% specific errors that can be described by this AVP are described in
%% the following section.
%% decode/3
decode(Name, #diameter_avp{code = Code, vendor_id = Vid} = Avp, Acc) ->
decode(Name, avp_name(Code, Vid), Avp, Acc).
%% decode/4
decode(Name, {AvpName, Type}, Avp, Acc) ->
d(Name, Avp#diameter_avp{name = AvpName, type = Type}, Acc);
decode(Name, 'AVP', Avp, Acc) ->
decode_AVP(Name, Avp, Acc).
%% d/3
%% Don't try to decode the value of a Failed-AVP component since it
%% probably won't.
d('Failed-AVP' = Name, Avp, Acc) ->
decode_AVP(Name, Avp, Acc);
%% Or try to decode.
d(Name, Avp, {Avps, Acc}) ->
#diameter_avp{name = AvpName,
data = Data}
= Avp,
try avp(decode, Data, AvpName) of
V ->
{H, A} = ungroup(V, Avp),
{[H | Avps], pack_avp(Name, A, Acc)}
catch
error: Reason ->
%% Failures here won't be visible since they're a "normal"
%% occurrence if the peer sends a faulty AVP that we need to
%% respond sensibly to. Log the occurence for traceability,
%% but the peer will also receive info in the resulting
%% answer-message.
diameter_lib:log({decode, failure},
?MODULE,
?LINE,
{Reason, Avp, erlang:get_stacktrace()}),
{Rec, Failed} = Acc,
{[Avp|Avps], {Rec, [rc(Reason, Avp) | Failed]}}
end.
%% decode_AVP/3
%%
%% Don't know this AVP: see if it can be packed in an 'AVP' field
%% undecoded, unless it's mandatory. Need to give Failed-AVP special
%% treatment since it'll contain any unrecognized mandatory AVP's.
%% Note that the type field is 'undefined' in this case.
decode_AVP(Name, #diameter_avp{is_mandatory = M} = Avp, {Avps, Acc}) ->
{[Avp | Avps], if Name == 'Failed-AVP';
not M ->
pack_AVP(Name, Avp, Acc);
true ->
unknown(Avp, Acc)
end}.
%% rc/1
%% diameter_types will raise an error of this form to communicate
%% DIAMETER_INVALID_AVP_LENGTH (5014). A module specified to a
%% @custom_types tag in a spec file can also raise an error of this
%% form.
rc({'DIAMETER', 5014 = RC, _}, #diameter_avp{name = AvpName} = Avp) ->
{RC, Avp#diameter_avp{data = empty_value(AvpName)}};
%% 3588:
%%
%% DIAMETER_INVALID_AVP_VALUE 5004
%% The request contained an AVP with an invalid value in its data
%% portion. A Diameter message indicating this error MUST include
%% the offending AVPs within a Failed-AVP AVP.
rc(_, Avp) ->
{5004, Avp}.
%% ungroup/2
-spec ungroup(term(), #diameter_avp{})
-> {avp(), #diameter_avp{}}.
%% The decoded value in the Grouped case is as returned by grouped_avp/3:
%% a record and a list of component AVP's.
ungroup(V, #diameter_avp{type = 'Grouped'} = Avp) ->
{Rec, As} = V,
A = Avp#diameter_avp{value = Rec},
{[A|As], A};
%% Otherwise it's just a plain value.
ungroup(V, #diameter_avp{} = Avp) ->
A = Avp#diameter_avp{value = V},
{A, A}.
%% pack_avp/3
pack_avp(Name, #diameter_avp{name = AvpName} = Avp, Acc) ->
pack_avp(Name, avp_arity(Name, AvpName), Avp, Acc).
%% pack_avp/4
pack_avp(Name, 0, Avp, Acc) ->
pack_AVP(Name, Avp, Acc);
pack_avp(_, Arity, Avp, Acc) ->
pack(Arity, Avp#diameter_avp.name, Avp, Acc).
%% pack_AVP/3
pack_AVP(Name, Avp, Acc) ->
case avp_arity(Name, 'AVP') of
0 ->
unknown(Avp, Acc);
Arity ->
pack(Arity, 'AVP', Avp, Acc)
end.
%% 3588:
%%
%% DIAMETER_AVP_UNSUPPORTED 5001
%% The peer received a message that contained an AVP that is not
%% recognized or supported and was marked with the Mandatory bit. A
%% Diameter message with this error MUST contain one or more Failed-
%% AVP AVP containing the AVPs that caused the failure.
%%
%% DIAMETER_AVP_NOT_ALLOWED 5008
%% A message was received with an AVP that MUST NOT be present. The
%% Failed-AVP AVP MUST be included and contain a copy of the
%% offending AVP.
%%
unknown(#diameter_avp{is_mandatory = B} = Avp, {Rec, Failed}) ->
{Rec, [{if B -> 5001; true -> 5008 end, Avp} | Failed]}.
%% pack/4
pack(Arity, FieldName, Avp, {Rec, _} = Acc) ->
pack('#get-'(FieldName, Rec), Arity, FieldName, Avp, Acc).
%% pack/5
pack(undefined, 1, FieldName, Avp, Acc) ->
p(FieldName, fun(V) -> V end, Avp, Acc);
%% 3588:
%%
%% DIAMETER_AVP_OCCURS_TOO_MANY_TIMES 5009
%% A message was received that included an AVP that appeared more
%% often than permitted in the message definition. The Failed-AVP
%% AVP MUST be included and contain a copy of the first instance of
%% the offending AVP that exceeded the maximum number of occurrences
%%
pack(_, 1, _, Avp, {Rec, Failed}) ->
{Rec, [{5009, Avp} | Failed]};
pack(L, {_, Max}, _, Avp, {Rec, Failed})
when length(L) == Max ->
{Rec, [{5009, Avp} | Failed]};
pack(L, _, FieldName, Avp, Acc) ->
p(FieldName, fun(V) -> [V|L] end, Avp, Acc).
%% p/4
p(F, Fun, Avp, {Rec, Failed}) ->
{'#set-'({F, Fun(value(F, Avp))}, Rec), Failed}.
value('AVP', Avp) ->
Avp;
value(_, Avp) ->
Avp#diameter_avp.value.
%% ---------------------------------------------------------------------------
%% # grouped_avp/3
%% ---------------------------------------------------------------------------
-spec grouped_avp(decode, avp_name(), binary())
-> {avp_record(), [avp()]};
(encode, avp_name(), avp_record() | avp_values())
-> binary() | no_return().
grouped_avp(decode, Name, Data) ->
{Rec, Avps, []} = decode_avps(Name, diameter_codec:collect_avps(Data)),
{Rec, Avps};
%% Note that a failed match here will result in 5004. Note that this is
%% the only AVP type that doesn't just return the decoded value, also
%% returning the list of component AVP's.
grouped_avp(encode, Name, Data) ->
encode_avps(Name, Data).
%% ---------------------------------------------------------------------------
%% # empty_group/1
%% ---------------------------------------------------------------------------
empty_group(Name) ->
list_to_binary(empty_body(Name)).
empty_body(Name) ->
[z(F, avp_arity(Name, F)) || F <- '#info-'(name2rec(Name), fields)].
z(Name, 1) ->
z(Name);
z(_, {0,_}) ->
[];
z(Name, {Min, _}) ->
lists:duplicate(Min, z(Name)).
z('AVP') ->
<<0:64/integer>>; %% minimal header
z(Name) ->
Bin = diameter_codec:pack_avp(avp_header(Name), empty_value(Name)),
<< <<0>> || <<_>> <= Bin >>.
%% ---------------------------------------------------------------------------
%% # empty/1
%% ---------------------------------------------------------------------------
empty(AvpName) ->
avp(encode, zero, AvpName).
