%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 2010-2015. All Rights Reserved. %% %% The contents of this file are subject to the Erlang Public License, %% Version 1.1, (the "License"); you may not use this file except in %% 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})). %% Tag common to generated dictionaries. -define(TAG, diameter_gen). %% Key to a value in the process dictionary that determines whether or %% not an unrecognized AVP setting the M-bit should be regarded as an %% error or not. See is_strict/0. -define(STRICT_KEY, strict). %% Key that says whether or not we should do a best-effort decode %% within Failed-AVP. -define(FAILED_KEY, failed). -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(). %% Use a (hopefully) unique key when manipulating the process %% dictionary. putr(K,V) -> put({?TAG, K}, V). getr(K) -> case get({?TAG, K}) of undefined -> V = erase({?MODULE, K}), %% written in old code V == undefined orelse putr(K,V), V; V -> V end. eraser(K) -> erase({?TAG, K}). %% --------------------------------------------------------------------------- %% # 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) -> {Avps, {Rec, Failed}} = lists:foldl(fun(T,A) -> decode(Name, T, A) end, {[], {newrec(Name), []}}, Recs), {Rec, Avps, Failed ++ missing(Rec, Name)}. %% Append 5005 errors so that a 5014 for the same AVP will take %% precedence in a Result-Code/Failed-AVP setting. newrec(Name) -> '#new-'(name2rec(Name)). %% 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. missing(Rec, Name) -> [{5005, empty_avp(F)} || F <- '#info-'(element(1, Rec), fields), A <- [avp_arity(Name, F)], false <- [have_arity(A, '#get-'(F, Rec))]]. %% Maximum arities have already been checked in building the record. have_arity({Min, _}, L) -> Min =< length(L); have_arity(N, V) -> N /= 1 orelse V /= undefined. %% 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}. %% 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 %% AVP is defined in the dictionary ... decode(Name, {AvpName, Type}, Avp, Acc) -> d(Name, Avp#diameter_avp{name = AvpName, type = Type}, Acc); %% ... or not. decode(Name, 'AVP', Avp, Acc) -> decode_AVP(Name, Avp, Acc). %% 6733, 4.4: %% %% Receivers of a Grouped AVP that does not have the 'M' (mandatory) %% bit set and one or more of the encapsulated AVPs within the group %% has the 'M' (mandatory) bit set MAY simply be ignored if the %% Grouped AVP itself is unrecognized. The rule applies even if the %% encapsulated AVP with its 'M' (mandatory) bit set is further %% encapsulated within other sub-groups, i.e., other Grouped AVPs %% embedded within the Grouped AVP. %% %% The first sentence is slightly mangled, but take it to mean this: %% %% An unrecognized AVP of type Grouped that does not set the 'M' bit %% MAY be ignored even if one of its encapsulated AVPs sets the 'M' %% bit. %% %% The text above is a change from RFC 3588, which instead says this: %% %% Further, if any of the AVPs encapsulated within a Grouped AVP has %% the 'M' (mandatory) bit set, the Grouped AVP itself MUST also %% include the 'M' bit set. %% %% Both of these texts have problems. If the AVP is unknown then its %% type is unknown since the type isn't sent over the wire, so the %% 6733 text becomes a non-statement: don't know that the AVP not %% setting the M-bit is of type Grouped, therefore can't know that its %% data consists of encapsulated AVPs, therefore can't but ignore that %% one of these might set the M-bit. It should be no worse if we know %% the AVP to have type Grouped. %% %% Similarly, for the 3588 text: if we receive an AVP that doesn't set %% the M-bit and don't know that the AVP has type Grouped then we %% can't realize that its data contains an AVP that sets the M-bit, so %% can't regard the AVP as erroneous on this account. Again, it should %% be no worse if the type is known to be Grouped, but in this case %% the RFC forces us to regard the AVP as erroneous. This is %% inconsistent, and the 3588 text has never been enforced. %% %% So, if an AVP doesn't set the M-bit then we're free to ignore it, %% regardless of the AVP's type. If we know the type to be Grouped %% then we must ignore the M-bit on an encapsulated AVP. That means %% packing such an encapsulated AVP into an 'AVP' field if need be, %% not regarding the lack of a specific field as an error as is %% otherwise the case. (The lack of an AVP-specific field being how we %% defined the RFC's "unrecognized", which is slightly stronger than %% "not defined".) %% d/3 d(Name, Avp, Acc) -> #diameter_avp{name = AvpName, data = Data, type = Type, is_mandatory = M} = Avp, %% Use the process dictionary is to keep track of whether or not %% to ignore an M-bit on an encapsulated AVP. Not ideal, but the %% alternative requires widespread changes to be able to pass the %% value around through the entire decode. The solution here is %% simple in comparison, both to implement and to understand. Strict = relax(Type, M), %% Use the process dictionary again to keep track of whether we're %% decoding within Failed-AVP and should ignore decode errors %% altogether. Failed = relax(Name), %% Not AvpName or else a failed Failed-AVP %% decode is packed into 'AVP'. Mod = dict(Failed), %% Dictionary to decode in. %% On decode, a Grouped AVP is represented as a #diameter_avp{} %% list with AVP as head and component AVPs as tail. On encode, %% data can be a list of component AVPs. try Mod:avp(decode, Data, AvpName) of V -> {Avps, T} = Acc, {H, A} = ungroup(V, Avp), {[H | Avps], pack_avp(Name, A, T)} catch throw: {?TAG, {grouped, RC, ComponentAvps}} -> {Avps, {Rec, Failed}} = Acc, {[[Avp | ComponentAvps] | Avps], {Rec, [{RC, Avp} | Failed]}}; error: Reason -> d(undefined == Failed orelse is_failed(), Reason, Name, trim(Avp), Acc) after reset(?STRICT_KEY, Strict), reset(?FAILED_KEY, Failed) end. %% trim/1 %% %% Remove any extra bit that was added in diameter_codec to induce a %% 5014 error. trim(#diameter_avp{data = <<0:1, Bin/binary>>} = Avp) -> Avp#diameter_avp{data = Bin}; trim(Avp) -> Avp. %% dict/1 %% %% Retrieve the dictionary for the best-effort decode of Failed-AVP, %% as put by diameter_codec:decode/2. See that function for the %% explanation. dict(true) -> case get({diameter_codec, dictionary}) of undefined -> ?MODULE; Mod -> Mod end; dict(_) -> ?MODULE. %% d/5 %% Ignore a decode error within Failed-AVP ... d(true, _, Name, Avp, Acc) -> decode_AVP(Name, Avp, Acc); %% ... or not. 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. d(false, Reason, Name, Avp, {Avps, Acc}) -> Stack = diameter_lib:get_stacktrace(), diameter_lib:log(decode_error, ?MODULE, ?LINE, {Reason, Name, Avp#diameter_avp.name, Stack}), {Rec, Failed} = Acc, {[Avp|Avps], {Rec, [rc(Reason, Avp) | Failed]}}. %% relax/2 %% Set false in the process dictionary as soon as we see a Grouped AVP %% that doesn't set the M-bit, so that is_strict() can say whether or %% not to ignore the M-bit on an encapsulated AVP. relax('Grouped', M) -> case getr(?STRICT_KEY) of undefined when not M -> putr(?STRICT_KEY, M); _ -> false end; relax(_, _) -> false. is_strict() -> false /= getr(?STRICT_KEY). %% relax/1 %% %% Set true in the process dictionary as soon as we see Failed-AVP. %% Matching on 'Failed-AVP' assumes that this is the RFC AVP. %% Strictly, this doesn't need to be the case. relax('Failed-AVP') -> is_failed() orelse putr(?FAILED_KEY, true); relax(_) -> is_failed(). is_failed() -> true == getr(?FAILED_KEY). %% reset/2 reset(Key, undefined) -> eraser(Key); reset(_, _) -> ok. %% decode_AVP/3 %% %% Don't know this AVP: see if it can be packed in an 'AVP' field %% undecoded. Note that the type field is 'undefined' in this case. decode_AVP(Name, Avp, {Avps, Acc}) -> {[Avp | Avps], pack_AVP(Name, Avp, Acc)}. %% 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 %% Length failure was induced because of a header/payload length %% mismatch. The AVP Length is reset to match the received data if %% this AVP is encoded in an answer message, since the length is %% computed. %% %% Data is a truncated header if command_code = undefined, otherwise %% payload bytes. The former is padded to the length of a header if %% the AVP reaches an outgoing encode in diameter_codec. %% %% RFC 6733 says that an AVP returned with 5014 can contain a minimal %% payload for the AVP's type, but in this case we don't know the %% type. pack_AVP(_, #diameter_avp{data = <<0:1, Data/binary>>} = Avp, Acc) -> {Rec, Failed} = Acc, {Rec, [{5014, Avp#diameter_avp{data = Data}} | Failed]}; pack_AVP(Name, #diameter_avp{is_mandatory = M, name = AvpName} = Avp, Acc) -> case pack_arity(Name, AvpName, M) of 0 -> {Rec, Failed} = Acc, {Rec, [{if M -> 5001; true -> 5008 end, Avp} | Failed]}; Arity -> pack(Arity, 'AVP', Avp, Acc) end. %% Give Failed-AVP special treatment since (1) it'll contain any %% unrecognized mandatory AVP's and (2) the RFC 3588 grammar failed to %% allow for Failed-AVP in an answer-message. pack_arity(Name, AvpName, M) -> IsFailed = Name == 'Failed-AVP' orelse is_failed(), %% Not testing just Name /= 'Failed-AVP' means we're changing the %% packing of AVPs nested within Failed-AVP, but the point of %% ignoring errors within Failed-AVP is to decode as much as %% possible, and failing because a mandatory AVP couldn't be %% packed into a dedicated field defeats that point. Note that we %% can't just test not is_failed() since this will be 'true' when %% packing an unknown AVP directly within Failed-AVP. pack_arity(IsFailed orelse {Name, AvpName} == {'answer-message', 'Failed-AVP'} orelse not M orelse not is_strict(), Name). pack_arity(true, Name) -> avp_arity(Name, 'AVP'); pack_arity(false, _) -> 0. %% 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. %% 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, Es} = decode_avps(Name, diameter_codec:collect_avps(Data)), [] == Es orelse throw({?TAG, {grouped, 5004, Avps}}), %% decode failure {Rec, Avps}; %% Note that this is the only AVP type that doesn't just return the %% decoded record, 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).